{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,30]],"date-time":"2025-07-30T16:17:13Z","timestamp":1753892233816,"version":"3.41.2"},"reference-count":38,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,6,9]],"date-time":"2022-06-09T00:00:00Z","timestamp":1654732800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:p><jats:bold>Introduction:<\/jats:bold> Victims of accidental hypothermia in hypothermic cardiac arrest (HCA) may survive with favorable neurologic outcome if early and continuous prehospital cardiopulmonary resuscitation (CPR) is started and continued during evacuation and transport. The efficacy of cerebral autoregulation during hypothermic CPR is largely unknown and is aim of the present experiment.<\/jats:p><jats:p><jats:bold>Methods:<\/jats:bold> Anesthetized pigs (<jats:italic>n<\/jats:italic> = 8) were surface cooled to HCA at 27\u00b0C before 3\u00a0h continuous CPR. Central hemodynamics, cerebral O<jats:sub>2<\/jats:sub> delivery (DO<jats:sub>2<\/jats:sub>) and uptake (VO<jats:sub>2<\/jats:sub>), cerebral blood flow (CBF), and cerebral perfusion pressure (CPP) were determined before cooling, at 32\u00b0C and at 27\u00b0C, then at 15\u00a0min after the start of CPR, and hourly thereafter. To estimate cerebral autoregulation, the static autoregulatory index (sARI), and the CBF\/VO<jats:sub>2<\/jats:sub> ratio were determined.<\/jats:p><jats:p><jats:bold>Results:<\/jats:bold> After the initial 15-min period of CPR at 27\u00b0C, cardiac output (CO) and mean arterial pressure (MAP) were reduced significantly when compared to corresponding values during spontaneous circulation at 27\u00b0C (\u221266.7% and \u221244.4%, respectively), and remained reduced during the subsequent 3-h period of CPR. During the first 2-h period of CPR at 27\u00b0C, blood flow in five different brain areas remained unchanged when compared to the level during spontaneous circulation at 27\u00b0C, but after 3\u00a0h of CPR blood flow in 2 of the 5 areas was significantly reduced. Cooling to 27\u00b0C reduced cerebral DO<jats:sub>2<\/jats:sub> by 67.3% and VO<jats:sub>2<\/jats:sub> by 84.4%. Cerebral VO<jats:sub>2<\/jats:sub> was significantly reduced first after 3\u00a0h of CPR. Cerebral DO<jats:sub>2<\/jats:sub> remained unaltered compared to corresponding levels measured during spontaneous circulation at 27\u00b0C. Cerebral autoregulation was preserved (sARI &amp;gt; 0.4), at least during the first 2\u00a0h of CPR. Interestingly, the CBF\/VO<jats:sub>2<\/jats:sub> ratio during spontaneous circulation at 27\u00b0C indicated the presence of an affluent cerebral DO<jats:sub>2<\/jats:sub>, whereas after CPR, the CBF\/VO<jats:sub>2<\/jats:sub> ratio returned to the level of spontaneous circulation at 38\u00b0C.<\/jats:p><jats:p><jats:bold>Conclusion:<\/jats:bold> Despite a reduced CO, continuous CPR for 3\u00a0h at 27\u00b0C provided sufficient cerebral DO<jats:sub>2<\/jats:sub> to maintain aerobic metabolism and to preserve cerebral autoregulation during the first 2-h period of CPR. This new information supports early start and continued CPR in accidental hypothermia patients during rescue and transportation for in hospital rewarming.<\/jats:p>","DOI":"10.3389\/fphys.2022.925292","type":"journal-article","created":{"date-parts":[[2022,6,9]],"date-time":"2022-06-09T06:59:11Z","timestamp":1654757951000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Autoregulation of Cerebral Blood Flow During 3-h Continuous Cardiopulmonary Resuscitation at 27\u00b0C"],"prefix":"10.3389","volume":"13","author":[{"given":"Sergei","family":"Valkov","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jan Harald","family":"Nilsen","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rizwan","family":"Mohyuddin","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Torstein","family":"Schanche","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Timofei","family":"Kondratiev","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gary C.","family":"Sieck","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Torkjel","family":"Tveita","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2022,6,9]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"45","DOI":"10.1161\/01.str.20.1.45","article-title":"Cerebral Autoregulation Dynamics in Humans","volume":"20","author":"Aaslid","year":"1989","journal-title":"Stroke"},{"key":"B2","doi-asserted-by":"publisher","first-page":"1138","DOI":"10.1093\/ejcts\/ezr316","article-title":"Studies of Isolated Global Brain Ischaemia: I A New Large Animal Model of Global Brain Ischaemia and its Baseline Perfusion Studies","volume":"41","author":"Allen","year":"2012","journal-title":"Eur. 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